With the increasing levels of performance of motor vehicles, a factor which is becoming more and more relevant in that respect is the question of uniformity of the tires used on such vehicles. A process for testing the uniformity of pneumatic tires and more particularly vehicle tires which provides that in a first measuring run a pneumatic tire which is mounted on a rim is rolled with a given radial loading against a testing drum, the radial force fluctuations which occur in that rolling operation are measured and corresponding measurement signals are produced, and evaluation of the measurement signals obtained during the measuring run results in values corresponding to the fluctuations in radial force, is to be found for example in `Werkstatt und Betrieb`, 1970, issue 3, pages 183 to 188, in the article by Kramer and Ohms `Einfluss der Kraftfahrzeugrader auf das Fahverhalten` [Influence of motor vehicle wheels on handling characteristics]. Thus, considerable importance is to be attached to the vehicle wheel and in particular the tire thereon, in regard to the handling characteristics of motor vehicles.
Various criteria are applied for the purposes of evaluating uniformity of a tire. In that respect, consideration is given in particular to the spring or resiliency characteristics of a tire which rolls under a loaded condition against a testing drum, in three axis directions which are mutually normal. The reaction forces which are produced in that situation are generally identified as tangential, radial and lateral forces. Ascertaining fluctuations in radial force is an aspect of significance as such fluctuations have a considerable influence on the rolling chassis and handling characteristics of a motor vehicle.
When carrying out measuring runs for testing the uniformity of pneumatic tires, the tires are mounted on measuring rim members or on conventional disc wheels and rolled against a testing drum at high speeds of up to around 112 mph. In that connection, hitherto no account was taken of the fact that the measurement result for ascertaining the profile in respect of fluctuations in radial forces of the tire can also be affected by radial defects or flaws in respect of the testing drum.